This invention relates generally to debris nets employed in connection with high rise construction projects, including structural steel beam structures, for catching debris which falls from uncompleted floors of the building. More particularly, this invention relates to devices and systems for adjusting the vertical height of perimeter debris nets as construction progresses.
Debris nets have been employed as safety barriers for a number of years to protect workers and others from falling debris at high rise construction projects. Various governmental and regulatory bodies have implemented safety regulations which specify the netting requirements, including the height of the netting in relation to the uncompleted portions of the construction project. Most pertinent safety regulations require that the debris net be raised as the construction project progresses through the upper portions of the structure.
A number of devices, including those disclosed in the patent literature, employ means for mounting the debris net to the high rise construction project, as well as means for sequentially mounting the debris net at increasing heights during the progress of the construction. While a number of devices employ means for efficiently mounting the debris net to the high rise structure, repositioning of the debris net to a new height is generally quite labor intensive and time consuming. Commonly, the debris net is completely dismounted from its supporting structure and is physically moved to the new height and remounted in position. Such a repositioning process is not only inefficient, but introduces certain safety deficiencies since there are periods of time in which the debris net is not functional or two levels of nets are required.
A number of devices have been proposed for implementing a more efficient method of raising the debris net from one height level to another as the construction progresses. Most of the technology has been directed to track-type systems wherein tracks of various forms are vertically mounted to the high rise structure. The debris net is mounted to supports which connect with the tracks. For example, U.S. Pat. No. 4,119,176 discloses a Y-shaped support structure for a debris net. The support structure is movably attached at two of its arms to a track which is vertically mounted adjacent to the face of the building. The arms are engaged in a slot in the track. The support structures and attached net are raised by removing the supports from the upper arms and sliding the ends of the upper arm upward while folding the net toward the building. The upper arms are then supported while simultaneously unfolding the support structure outwardly and finally providing a support for the bottom arms of the Y-shaped support structures.